T-4 (P)
supersonic transport

    In 1963 and 1964, the Sukhoi Design Bureau designed several passenger versions of the T-4. All configurations were canards with a low wing. Powerplant positioning was the only variable that was changed.
    Fuselage: The fuselage was divided into a forward section, a center section and a rear section.
    In the forward fuselage, a radome covered the radar. An electronic equipment bay was behind the radome. The crew cockpit was in the upper fuselage, behind the electronic equipment bay. The pilot and copilot sat side-by-side with a narrow passage between the seats. Navigator and radio operator seats were installed along the right side of the fuselage. The canopy was equipped with hoods which covered the canopy in cruise flight. During takeoff and landing, the hoods lowered providing a forward view. A nose gear well was underthe cockpit. The nose gear strut had paired wheels. A luggage section, with a wardrobe and a toilet, was behind the cockpit. The front entry door was on the left fuselage side.
    The center fuselage contained two passenger cabins. Each cabin could seat 32 passengers. They were equipped with eight rows of seats, four abreast, with a passage between them. A second entry door and the galley were between the two cabins. At the front of the forward passenger cabin were the wardrobe and the toilet. The rear fuselage contained two fuel tanks, including one supply fuel tank, and the brake parachute compartment.
    Wing: The first version of the wing was almost a delta plan form. The wing trailing edge was beveled. Two engine nacelles were mounted under each outer wing. The engine intakes were not equipped with the boundary layer air bleed system because they extended forward and the engine nacelles were mounted far from the fuselage. An integral fuel tank was mounted in the wing center section.
    The second version of the aircraft was equipped with a tapered wing with the tips, approximately one-third of each wing, deflected downwards. The powerplant was mounted in one engine nacelle under the wing center section.
    Both aircraft versions had delta forward control surfaces, mounted in the forward fuselage. These included stabilizers and elevators.
    Empennage: An all-moving vertical tail unit, of small area, was mounted on the rearfuselage. Additionally, the first aircraft version had a fixed ventral fin.
    Landing gear: The aircraft had a tricycle configuration. The nose gear was equipped with paired wheels and retracted inside the fuselage. In the first version of the aircraft, the main gear struts, with four wheels, retracted into the engine nacelles. The second version had the main gear retracting in so-called "breeches" which were installed on the engine nacelle sides. These also served as additional ventral fins.
    Powerplant: Four engines were used. The first aircraft version had the engines mounted under each outer wing in pairs. Each engine nacelle air intake was equipped with a single, vertical ramp for the two engines. The second version was equipped with four engines, mounted in one engine nacelle under the wing center section. Each engine had a separate intake with a variable horizontal ramp. The air intakes were mounted close to the wing lower surface. Thus, they were equipped with a boundary layer air bleed system.

References and Credits:

1. «Bombers» / V.Il'in, M.Levin, 1997 /
2. Near to Sukhoi. Memoirs of the aircraft designer / O.S.Samoilovich /
3. OKB Sukhoi, A History of the Design Bureau and its Aircraft, 1996